Turbulator



April 27, 1954 G. H. DIEHL ET AL 2,676,64

TURBULATOR Filed June 11, 1952 f1? van zars Gordon H Die/5] Robert M Ha101 75 1 Z By P Wm, My? 2775]) fizfarneys Patented Apr. 27, 1954 GordonH. 'Diehl and Robert M. Hopkins, Rochester, N. Y. 'assignors to GeneralMotors Corporation,'Detroit, 'Mich., a'corporation of DelawareApplication .lunell, 1952, Serial No. 292,932

6 Claims.

This invention relates to oil burners and has to do with providing acombustible mixture of liquid fuel and air for eflicient heatingpurposes.

The present invention is best adapted to oil burners having an hourlyrate of fuel consumption of approximately 1.25 to 1.65 gallons per hourbut is not limited to this range.

Itis particularly adapted to oil burners of the pressure atomizing typewherein air is supplied by a blower to a draft tube which is outfittedcentrally with a fuel line terminating in an atomizing nozzle and anelectric igniter mounted close to the nozzle. Conventionalpressureatomizing oil burners are of this general construction.

Many and complicated devices have been used hitherto in an attempt tomix the air in the drafttube with the atomized fuel coming from thenozzle so that combustion will be asnearly complete as possible. Inactual practice an oil burner should be quietin operation, combustionshould be as nearly complete as possible to avoid formation of soot andthe flame should be stable under various conditions of application suchas variations in the construction and operation of the chimmey or stack.

7 It is an object of the present invention to achieve these desirablefeatures in a simple manner.

panying drawings wherein a preferred embodiment of the present inventionis clearly shown.

In the drawing; g Fig. 1 is a partial sectional view of the fueldischarge end of an oil burner draft tube assembly.

Fig. 2 is a sectional view of the burner draft tube assembly on line 22of Fig. 1. I

With particular reference to the drawings l0 refers to a draft tube thatis designed to conduct air under pressure to thefinterior of thefurnace, and I2 is an oil pipe fitted with a nozzle adapter I4 providedwith an atomizing nozzle l6 designed to deliver fuel inatomized form, ina cone of mist somewhat as indicated at l8. In-

: sulators 20 support electrodes 22 that extend to close proximity ofcone [8 of atomized fuel. The

atomized fuel I8 is ignited by a spark at the end of electrodes 22 andafter the spark is shut off the cone of fuel will continue to burn aslong as p the fuel supply is maintained.

Air from the tube l0 must be mixed with the cone of fuel I8 and themanner in which thisis brought aboutis a subject of the presentinvention. In this instance a turbulator 24 incorporates a bushing 26disposable over the oil pipe I2 where it may be secured by a set screw28 and cooperates with a set screw 30 passing through clip members 32,and 34 for supporting the insulators 20 of electrodes '22. A hub 35 ofbushing 26 passes through an aperture in a head member 36 where it issecured as at 38.

The head member 36 is also apertured for passage of insulators 20 but isotherwise'impervious.

The head member 36 provides a closure for a cylindrical drum 4!] of theturbulator proper.

The drum 40 is provided byr'olling up a blank of sheet metal to providea cylinder for surrounding the fuel nozzle and electrodes, with the fuelnozzle disposed centrally thereof. f The blanking of the cylindercomprises shearing on three sides of a rectangle to providelongitudinally extending openings 43 within vanes or fins 42 boundedaround three edges by short end portions 44 and 46 connected by freeedge 48.

This sheared'portion or vane 42 is left flat so as'to extend as atangent from the root portion 50 when the blank is rolled into acylinder.

Rectangular openings 64 are arranged in one end 'of the drum with theircenters coinciding with the general plane at the tip end of the nozzlel6. These openings 64 are arranged at the outer end of the drum and inthe root portion of the vanes 42, that is to say, they are generallycentered about the line joining the unsheared portion of the vanes. Whenrolled that leaves cylindrical bands 52 and 54 at each end of theturbulator with outwardly finned portions 42. The end of the cylindricalband 52 is bonded to the head member 36 and the cylindrical band 54 ispiloted in a central aperture 56 of an end plate 58. v

Angle brackets '60 secured to the end plate 58 are receptive of screwdevices 62 for mounting the end plate 58 at the end of the draft tubeIll.

A frusto conical deflector 66 is provided witha flange 68 which isbonded to the plate 58.

flows through the apertures 10 directly into the combustion chamber.

The air which flows beneath the vanes 42 passes into the drum 40 andsets up the equivalent of a cyclone within the drum. This stream of airmoves forward in the drum to its open end and in the course of itspassage mixes with the cone of atomized fuel l8. It is deflectedsomewhat toward the cone of fuel by the deflector 66. A thorough mixingof air and fuel is thereby attained.

The air which flows through the openings 64 is believed to pass almostradially into the drum 40 and the purpose of this air stream is toreduce the noise of the burner flame. It is practically impossible todetermine just what takes place but tests show a marked reductioninflame noise.

The air which flows through the apertures 10 passes into the combustionchamber, not shown, and mixes with the flame coming from the burner.This stream of air further reduces the flame noise.

Burners have been tested using the construction herein disclosed and itwas found possible to burn fuel oil with a 13% CO2 flue gas content andwith a very low soot deposit. The flame was very stable under varyingdraft conditions and the burner operation was quiet.

While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

I. In an oil burner having a draft tube and an oil atomizing nozzle for'eifecting combustion of a liquid fuel, a turbulator disposed at theexit end of the draft tube and "encompassing said fuel nozzle, saidturbulator comprising a cylindrical cup having openings and exteriorfins adjacent thereto admitting air tangentially from the draft tube tothe region of the fuel nozzle along a gyratory path, said turbulatorhaving surface openings located in the roots of said fins admitting airalong radial paths from the draft tube substantially in the plane ofsaid fuel nozzle, whereby the air in the draft tube passing thru theturbulator is mixed with the atomized fuel to provide a combustiblemixture, and plate means closing the end of the draft tube andsupporting one end of the turbulator, said plate means having openingspermitting restricted lineal flow from the draft tube and for creating apressure head for the tangential flow and the radial flow from the drafttube to the interior of the turbulator.

Z. In an oil burner, a draft tube, an oil pipe and fuel nozzle centrallydisposed in the draft tube, a turbulator supported by the oil pipe andcircumscribing the fuel nozzle, an annular plate across the spacebetween the turbulator and draft tube, said annular plate having aseries of apertures permitting restricted air flow from the draft tube,said turbulator comprising a cylindrical portion having openingsbordered by exterior fins admitting air into the turbulator back of thefuel nozzle, and having openings thru the roots of said fins in theregion'of said fuel nozzle for admitting radially moving air to theinterior of said turbulator for mixing with the tangentially admittedair to effect air currents of maximum turbulence in the region of fueldischarge from said nozzle, and a frusto conical deflector supported bythe annular plate separating the lineal moving air from the turbulatedmoving air and for deflecting the latter toward the fuel nozzle insuringa combustible mixture in front of the fuel nozzle.

3. In an oil burner, a draft tube providing a directed flow of air forsupporting combustion, a fuel pipe supported at the axis of said drafttube and provided with a fuel nozzle at the normally open end of saidtube, a turbulator supported by the oil pipe and disposed about saidfuel nozzle, an annular head member supported by the end of the drafttube and spanning the space between the draft tube and the turbulator,said turbulator comprising a cylindrical drum piloted in said annularhead member and having circumferentially spaced openings, a head memberclosing the other end of the drum and said drum having longitudinalopenings bounded on one side thereof by tangentially extending finsstruck outwardly from the surface of said drum for admitting air in aswirling motion to the interior of said turbulator and on the rear sideof said fuel nozzle, and a circumferential series of openings throughthe root portion of said fins disposed in a plane at one end of saiddrum substantially coincident with the end of said fuel nozzle.

4. In an oil burner, 'a draft tube providing a flow of air to acombustion chamber, a fuel pipe coaxially disposed within said drafttube and terminating in an atomizing nozzle, a turbulator forconditioning the air for mixing with the atomized fuel, said turbulatorcomprisinga drum coaxially disposed about said fuel pipe and within saiddraft tube to substantially enclose said atomizing nozzle, said drumcomprising a cylindrical structure having a closed end on one side ofthe atomizing nozzle, said turbulator having openings in thecircumference of said cylindrical structure for the admission of a firstair stream from the draft tube to the interior of said cylindricalstructure, exterior tangentially arranged finsbo'un'ding one edge ofsaid openings for directing the first air stream along the inner surfaceof said cylindrical structure, an annular plate at the terminating endof the draft tube piloting one end of the cylindrical structure andspanning the annular space between the draft ube and turbulator, saidturbulator having openings in said cylindrical structure disposed in theroots of said fins providing for admission of a second air stream fromsaid draft tube to the interior of said cylindrical structure, theopenings for admission'of said first and said second stream air beingstaggered for intermixing air in a zone coincident with emission ofatomized fuel to produce an atmosphere of ignitible and combustible fuelin close proximity to the terminus of the draft tube. v

'5. The combination set forth in claim 4 wherein the annular platepiloting one end of the cylindrical structure is apertured and forms apressure head for restricting lineal movement of air in the draft tubeand for assisting in radial movement of air through said openings in theroots of said fins.

6. In an oil burner having a draft tube and an 'oil atomizing nozzle foreffecting-"combustion of a liquid fuel, a turbulator disposed at theexit end "of the draft tube and encompassing said fuel "nozzle, anannular plate at the end of the draft tube supporting the concentricallyarranged turbulator, said turbulator comprising a cylindrical cup-likedrum having its open end piloted into the annular plate, and having aseries of openings through the wall portion with tangentially arrangedfins for admitting an air stream of cyclonic nature which moves forwardwithin the drum and mixes with the cone of atomized fuel, saidturbulator having a series of surface openings located in the roots ofsaid fins admitting air flow along radial paths from the draft tubesubstantially at the plane of the fuel nozzle for reducing the noise ofburner flame, and a defiector disposed over the open end of theturbulator for directing the air movement from both of said sets ofopenings into the path of the atomized fuel, said annular platesupporting the turbulator at the end of the draft tube and having aseries of openings for lineal flow of air from the draft tube into thecombustion chamber outside of the burner flame, and for restricting thelineal flow of air so that tangentially and radially moving air streamsfrom the draft tube through the drum will be enforced.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,221,519 Jones et a1 Nov. 12, 1940 2,262,525 De Lancey Nov.11, 1941 2,304,294 Wood Dec. 8, 1942 2,500,344 Carter Mar. 14, 19502,502,664 Nest Apr. 4, 1950 2,513,645 Hallinan July 4, 1950 2,516,063Logan et a1 July 18, 1950

